DO not be alarmed if you see scores of runners making a dash from the Esplanade Hotel’s Ball and Chain pub clad in nothing but their underwear.

In Fremantle for the first time just a few days after Valentine’s Day, the Cupid’s Undie Run urges people to strip down to their underwear in a fundraising effort for The Children’s Tumour Foundation (CTF), an organisation that helps children living with neurofibromatosis.

CTF national events and fundraising manager Katrina Stuve said the run had grown in popularity since it started in Sydney in 2014.

“We put it down to the fun, loving Valentine’s aspect of the event which also has a serious side to it,” she said.

“We encourage fancy dress like cupid’s wings and tutus. Do something daring and challenge yourself. The run isn’t that long, but running in your undies might feel like it is.

“We need to make people aware of this genetic disorder neurofibromatosis that has no cure and affects 1 in 2500 people.

“I think it’s important that those who are affected know that The Children’s Tumour Foundation can help them. We currently have two support coordinators and with the fundraising dollars we raise at Cupid’s this year we are hoping to add another one.”

Ms Stuve said the organisation was hoping to raise $375,000 nationally through the event.

The Cupid’s Undie Run kicks off from the Ball and Chain from 12pm on February 19.